Support cushion



FIG. 1 is a top, front, and left side perspective view of a support cushion showing my new design;

FIG. 2 is a top, front, and right side perspective view thereof, shown in an opened position; and

FIG. 3 is a bottom, rear, and right side perspective view thereof, shown in an opened position. 

The ornamental design for a support cushion, as shown and described. 